Passenger&#39;s weight measurement device for vehicle seat

ABSTRACT

To realizes an easy maintenance of the load sensor. 
     A passenger&#39;s weight measurement device  1  comprises a left and right pair of fixed lower rails  3  which are fixed on the vehicle floor, a left and right pair of movable upper rails  4  which are disposed to move in a front-and-rear direction on the fixed lower rail  3,  load sensors  50  and  60  which are fixed to an upper surface of the right movable upper rail  4,  load sensors  70  and  80  which are disposed on the movable upper rail  4  to be movable in a left-and-right direction with respect to the right movable upper rail  4,  a sub frame  110  which is mounted on the load sensors  50, 60, 70,  and  80,  side frames  141  and  142  which are welded to the sub frame  110,  and a pan frame  143  which is detachably disposed to the side frames  141  and  142  to cover the front of the side frames  141  and  142.  A gouged section  151  is formed on the side frame  141.

The present application is a divisional application of application Ser.No. 11/632,403 filed Jan. 12, 2007, which is National Stage Applicationof PCT/JP2005/013945 filed Jul. 29, 2005, which claims priority fromJapanese Patent Application No. 2004-223456 filed Jul. 30, 2004. Thedisclosure of each of the prior applications is hereby incorporated byreference in its entirety.

TECHNICAL FIELD

The present invention relates to a passenger's weight measurement devicefor a vehicle seat which measures a weight of a passenger who sits on avehicle seat.

BACKGROUND ART

Recently, to improve performance of various safety devices such as aseat belt and an air bag, operations of the safety devices have beencontrolled in accordance with a weight of a passenger sitting on avehicle seat in some cases. In the conventional passenger's weightmeasurement device for measuring a weight of a seated passenger, a loadsensor is disposed between a vehicle floor and the vehicle seat (Forexample, refer to Patent Document 1 and Patent Document 2).

Patent Document 1: Japanese Patent Document 10-297334

Patent Document 2: Japanese Patent Document 11-304579

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

However, because the load sensor is disposed in a narrow space betweenthe vehicle floor and the vehicle seat, it is difficult to domaintenance on the load sensor. Further, if the entire vehicle seat isdismounted for easier maintenance, the working efficiency of themaintenance is to be inefficient.

An object of the present invention is to realize the easy maintenance ofthe load sensor.

Means for Solving the Problem

To solve the aforementioned problems, in accordance with a first aspectof the present invention, a passenger's weight measurement device for avehicle seat comprises a movable rail disposed to be movable in afront-and-rear direction on a fixed rail fixed to a vehicle side, a loadsensor which is mounted on an upper surface of the movable rail, acushion frame which is mounted on the load sensor, and a pan frame whichis detachably disposed on the cushion frame to cover the cushion framefrom above at an upper side of the load sensor.

As described above, because the pan frame is detachably mounted on thecushion frame, the maintenance of the load sensor can be done by onlydismounting the pan frame. In such way, the maintenance of the loadsensor can be done without decomposing/disassembling the cushion frameof the vehicle seat. Thus, the efficiency of the load sensor maintenanceis improved.

In accordance with the first aspect of the invention, preferably, thepan frame is tightened to the cushion frame by a screw.

As described above, because the pan frame is tightened to the cushionframe by a screw, the pan frame can be dismounted from the cushion framejust by loosening the screw.

In accordance with the first aspect of the invention, preferably, thecushion frame has a gouged section formed on a side so as to avoid theload sensor when seen from above.

As described above, because a gouged section is formed on the cushionframe, the maintenance of the load sensor can be done from above withoutdisassembling the cushion frame. Thus, the efficiency of the load sensormaintenance is improved.

Further, in accordance with a second aspect of the present invention, apassenger's weight measurement device for a vehicle seat comprises amovable rail disposed to be movable in a front-and-rear direction on afixed rail fixed to a vehicle side, a load sensor which is mounted on anupper surface of the movable rail, and a cushion frame which is mountedon the load sensor, wherein the cushion frame has a gouged sectionformed on a side so as to avoid the load sensor when seen from above.

As described above, because a gouged section is formed on the cushionframe, the maintenance of the load sensor can be done from above withoutdecomposing/disassembling the cushion frame. Thus, the efficiency of theload sensor maintenance is improved.

Effect of the Invention

According to the present invention, the load sensor maintenance can bedone easily without decomposing/disassembling the cushion frame for thevehicle seat. Thus, the efficiency of the load sensor maintenance isimproved.

BRIEF DESCRIPTION OF THE DRAWINGS

[FIG. 1] This is a perspective view showing a passenger's weightmeasurement device 1 for a vehicle seat.

[FIG. 2] This is an exploded perspective view showing a passenger'sweight measurement device 1.

[FIG. 3] This is a plan view showing a passenger's weight measurementdevice 1.

[FIG. 4A] This is a side view showing an attachment structure of asubmarine pipe 11.

[FIG. 4B] This is a plan view showing an attachment structure of asubmarine pipe 11.

[FIG. 4C] This is a schematic sectional diagram cut along the line IV-IVof FIG. 4B.

[FIG. 5] This is a perspective view showing a left load sensor 50.

[FIG. 6] This is an exploded perspective view showing an attachmentstructure of a load sensor 60.

[FIG. 7] This is a perspective view showing a right load sensor 70.

[FIG. 8] This is an exploded perspective view showing an attachmentstructure of a load sensor 80.

[FIG. 9] This is a perspective view showing a passenger's weightmeasurement device 1 in a state where a pan frame 143 is dismounted.

BEST MODE FOR CARRYING OUT THE INVENTION

The preferred embodiments of the present invention will be describedbelow with reference to the accompanying drawings. In the embodimentsbelow, various technical preferable limitations are added to carry outthe invention. However, the scope of the invention is not limited to theembodiment described below and the examples shown in the drawings.

FIG. 1 is a perspective view showing a passenger's weight measurementdevice 1 for a vehicle seat, FIG. 2 is an exploded perspective viewshowing a passenger's weight measurement device 1, and FIG. 3 is a planview showing a passenger's weight measurement device 1 seen from above.In each of the drawings, arrows indicating up-and-down, left-and-right,and front-and-rear correspond to the directions as seen from a passengerseated in the vehicle seat.

The passenger's weight measurement device 1 is mounted on the bottom ofa seat cushion which a passenger sits on. Further, the passenger'sweight measurement device 1 is for the right side seat of the vehicleseat, and a buckle for a seatbelt is provided at the left side of thepassenger's weight measurement device 1 and a tongue plate of theseatbelt is to be fastened by this buckle.

As shown in FIGS. 1, 2, and 3, a pair of left and right seat-sliders 2parallel to each other are disposed on the floor of the passengercompartment. Both of the seat-sliders 2 comprise a fixed lower rail 3which extends in a front-and-rear direction of the vehicle and is fixedto the floor of the passenger compartment, and a movable upper rail 4which is engaged with the fixed lower rail 3 to be slidable in afront-and-rear direction on the fixed lower rail 3 with respect to thefixed lower rail 3.

A left end of the lower bracket 5 is fixed to the lower surface of theleft fixed lower rail 3 by a bolt and nut connection 6, and a right endof the lower bracket 5 is fixed to the lower surface of the right fixedlower rail 3 by a bolt and nut connection 7. The lower bracket 5 iscrossed between the left and right fixed lower rails 3 and improves therigidity to suppress the variable of a space between the left and rightfixed lower rails 3.

The bracket 8 is fixed to the middle portion of the left movable upperrail 4 in a front-and-rear direction on an upper surface thereof by abolt and nut connection 10, and the bracket 9 is fixed to the middleportion of the right movable upper rail 4 in a front-and-rear directionon an upper surface thereof by a bolt and nut connection. Both brackets8 and 9 are formed in an L-shape when seen from the front and they aredisposed so as to erect them with respect to the upper surface of eachof the movable upper rails 4 respectively.

In between the brackets 8 and 9, a submarine pipe 11 is provided. Here,the brackets 8 and 9 and the submarine pipe 11 will be described indetail with reference to FIGS. 4A to 4C. FIG. 4A is a left side view,FIG. 4B is a top view, and FIG. 4C is a schematic sectional diagram cutalong the line IV-IV of FIG. 4B.

A mounting hole which penetrates in a left-and-right direction is formedon the left bracket 8 and the left end of the submarine pipe 11 isinserted into the mounting hole. Further, the bracket 8 and thesubmarine pipe 11 are fixed by welding.

A mounting hole which penetrates in a left-and-right direction is alsoformed on the right bracket 9 and the ring-shaped nylon bush 12 isfitted in the mounting hole. The bush 12 is latched by the bracket 9along the edge of the mounting hole, and the moving of the bush 12 inthe penetration direction of the mounting hole is deterred. The rightend of the submarine pipe 11 is inserted into the bush 12, and thesubmarine pipe 11 can slide in the penetration direction of the mountinghole with respect to the bush 12. Moreover, the sectional area of thesubmarine pipe 11 at a predetermined distance apart towards the rightend of the submarine pipe 11 from the mounting hole of the bracket 9(here, the area at the right end) is formed to be larger than the areaof the mounting hole. Particularly, the submarine pipe 11 is provided ina shape where the opening of the submarine pipe 11 becomes larger as itapproaches the right end in the right side of the mounting hole of thebracket 9 (trumpet shape) to prevent the submarine pipe 11 from fallingout from the bush 12 and the mounting hole. By providing a frange at theright end of the submarine pipe 11, the sectional area of the submarinepipe 11 including the frange can be made larger than the mounting holeand the submarine pipe 11 may be prevented from falling out from thebush 12 and the mounting hole by the frange.

In the present embodiment, the submarine pipe 11 is fixed to the leftbracket 8 and can slide in a left-and-right direction with respect tothe right bracket 9. However, the submarine pipe 11 may slide in aleft-and-right direction with respect to the left bracket 8 and may befixed to the right bracket 9. Further, the submarine pipe 11 may slidein a left-and-right direction with respect to both left and rightbrackets 8 and 9.

As shown in FIGS. 1 and 2, a load sensor 50 is mounted on the front endof the upper surface of the left movable upper rail 4, and a load sensor60 is mounted on the rear end of the upper surface of the left movableupper rail 4. The load sensors 50 and 60 detect the load as anelectrical signal.

The left front load sensor 50 will be described with reference to FIG.5. FIG. 5 is a perspective view showing the left front load sensor 50.As shown in FIG. 5, the left front load sensor 50 comprises acolumn-shaped sensing unit 52 which detects the load, a plate-likefrange 51 which horizontally extends in a front direction and in a reardirection from the bottom end of the sensing unit 52, a load input rod53 which extends upward from an upper end of the sensing unit 52, and aconnector 54 which extends from the sensing unit 52 to become horizontalwith the frange 51. At the front and the rear of the frange 51, malescrew shaped circular holes 55 which penetrate in an up-and-downdirection are formed respectively, and one of the circular holes 55 islocated directly beneath the connector 54. A screw thread is formed onthe periphery of the load input rod 53. Moreover, the sensing unit 52incorporates a strain gauge, and the load is converted to an electricalsignal by the strain gauge.

FIG. 6 is an exploded perspective view showing a rear end of the leftmovable upper rail 4. As shown in FIG. 6, similar to the left front loadsensor 50, the left rear load sensor 60 comprises a frange 61, a sensingunit 62, a load input rod 63, and a connector 64. References having thesame last single digit are assigned to the corresponding parts of theleft front load sensor 50 and the left rear load sensor 60, and thedescription for each part of the left rear load sensor 60 is omitted.

The left rear load sensor 60, as shown in FIG. 6, is disposed on therear end of the left movable upper rail 4. The lower surface of thefrange 61 abuts the upper surface of the left movable upper rail 4, andthe male screws 67 and 67 which penetrate the movable upper rail 4 frombottom up engage with the circular holes 65 and 65. By the tightening ofthe male screws 67 and 67, the movable upper rail 4 is held between theheads of the male screws 67 and 67 and the frange 61. In such way, theload sensor 60 is fixed to the upper surface of the movable upper rail4. On the other hand, as shown in FIGS. 1 and 2, similar to the case ofthe load sensor 60, the left front load sensor 50 is fixed to the frontupper surface of the movable upper rail 4 by engaging the male screws 57and 57 which penetrate the movable upper rail 4 from bottom up with thecircular holes 55 and 55. Here, the tip of the connector 54 is directedbackward for the left front load sensor 50, while the tip of theconnector 64 is directed forward for the left rear load sensor 60.

As shown in FIG. 2, a load sensor 70 is mounted on the front end of theupper surface of the right movable upper rail 4, and a load sensor 80 ismounted on the rear end of the upper surface of the right movable upperrail 4. The load sensors 70 and 80 are provided to detect the load as anelectrical signal.

The right front load sensor 70 will be described with reference to FIG.7. FIG. 7 is the perspective view showing the right front load sensor70. As shown in FIG. 7, the right front load sensor 70 comprises acolumn-shaped sensing unit 72 which detects the load, a plate-likefrange 71 which horizontally extends in the front direction and in therear direction from the bottom end of the sensing unit 72, a load inputrod 73 which extends upward from the upper end of the sensing unit 72,and a connector 74 which extends from the sensing unit 72 to becomehorizontal with the frange 71. An elongated hole 75 which penetrates thefrange 71 in an up-and-down direction and has a left-and-right directionas the longitudinal direction is formed on either front part or backpart of the frange 71, and a notch 76 which has an opening at the edgealong the longitudinal direction of the frange 71 and has aleft-and-right direction as the longitudinal direction is formed on theother part. The notch 76 is formed on the frange 71 directly beneath theconnector 74. A screw thread is formed on the periphery of the loadinput rod 73. Moreover, the sensing unit 72 incorporates a strain gauge,and the load is converted to an electrical signal by the strain gauge.

FIG. 8 is an exploded perspective view showing a rear end of the movableupper rail 4. As shown in FIG. 8, similarly to the right front loadsensor 70, the right rear load sensor 80 comprises a frange 81, asensing unit 82, a load input rod 83, and a connector 84. Referenceshaving the same last single digit are assigned to the correspondingparts of the right front load sensor 70 and the right rear load sensor80, and the description of each part of the right rear load sensor 80 isomitted.

The right rear load sensor 80 is disposed on the rear end of the rightmovable upper rail 4 as shown in FIG. 8. A slide plate 89 havingapproximately the same shape as the planar shape of the frange 81 abutsthe lower surface of the frange 81, and the frange 81 is grasped by fourpawls 90 formed at the edge of the slide plate 89. On the slide plate89, an elongated hole 89 a which penetrates the slide plate 89 in anup-and-down direction and has a left-and-right direction as thelongitudinal direction is formed. Further, a notch 89 b which has anopening at the edge along the longitudinal direction of the slide plate89 and has a left-and-right direction as the longitudinal direction isformed on the slide plate 89. The elongated hole 89 a corresponds to theelongated hole 85 of the load sensor 80, and the notch 89 b correspondsto the notch 86 of the load sensor 80.

The frange 81 is disposed on the upper surface of the movable upper rail4 in a state where the slide plate 89 abuts the upper surface of theright movable upper rail 4. Further, the level screw 87 which isinserted into the ring-shaped damper 91 and the slide member 92 isinserted into the elongated hole 85 from above as a slider, and thelevel screw 87 is disposed so as to erect it with respect to the uppersurface of the movable upper rail 4 by engaging the level screw 87 withthe movable upper rail 4. The slide plate 89, the frange 81, the slidemember 92, and the damper 91 are held between the head of the levelscrew 87 and the movable upper rail 4, and the level screw 87 can slidein the longitudinal direction of the elongated hole 85.

Further, the level screw 88 which is inserted into the ring-shapeddamper 93 and the slide member 94 is engaged with the movable upper rail4 so as to erect it on the upper surface of the movable upper rail 4,and the level screw 88 is inserted into the notch 86 as the slider. Theslide plate 89, the frange 81, the slide member 94, and the damper 93are held between the head of the level screw 88 and the movable upperrail 4, and the level screw 88 can slide in the longitudinal directionof the notch 86. In such way, the level screw 87 slides in thelongitudinal direction of the elongated hole 85, and the level screw 88slides in the longitudinal direction of the notch 86. Therefore, theright rear load sensor 80 can slide in a left-and-right direction withrespect to the right movable upper rail 4 in the range between the pointwhere the level screw 87 abuts the right end of the elongated hole 85and the point where the level screw 87 abuts the left end of theelongated hole 85.

The mounting instruction for the right rear load sensor 80 is asdescribed below. First, the level screw 88 is inserted into the damper93 and the slide member 94, in this order, and the level screw 88 isengaged with the movable upper rail 4 so as to erect it on the uppersurface of the movable upper rail 4. However, the head of the levelscrew 88 is to be apart from the upper surface of the movable upper rail4. Next, the slide plate 89 is fitted to the frange 81 of the right rearload sensor 80, and the frange 81 is grasped by the pawls 90 of theslide plate 89. Then, the frange 81 is to abut the upper surface of themovable upper rail 4 via the slide plate 89, and the level screw 88 isinserted into the damper 91 and the slide member 92, in this order.Further, the level screw 87 is inserted into the elongated hole 85 andthe level screw 87 is engaged with the movable upper rail 4. At thisstate, the level screw 88 is not in the notch 86. Next, by rotating theright rear load sensor 80 centering the level screw 87, the level screw88 is inserted into the opening of the notch 86 at the edge of thefrange 81 and the level screw 88 is latched by the notch 86. In suchway, because the notch 86 is located directly beneath the connector 84,the connector 84 becomes an obstacle and the level screw 88 cannot beinserted into the notch 86 from above to be engaged with the movableupper rail 4. However, because the level screw 88 is engaged with themovable upper rail 4 beforehand and the notch 86 has an opening at theedge of the frange 81, the level screw 88 can be inserted into the notch86 by the rotation of the load sensor 80. Moreover, because the frange81 is held between the head of the level screw 88 and the movable upperrail 4, the load sensor 80 does not depart upward easily. In addition,because the frange 81 of the load sensor 80 is grasped by the pawls 90,the slide plate 89 does not slide with respect to the frange 81 when theload sensor 80 rotates.

The lower surface of the slide plate 89 is coated by a resin or the likeso that the slide plate 89 is easily slid with respect to the movableupper rail 4. Instead of providing the coated slide plate 89, the frange81 can be made to be easily slid with respect to the movable upper rail4 by coating the lower surface of the frange 81 with a resin or thelike.

As shown in FIG. 2, the right front load sensor 70 is mounted on theupper surface of the movable upper rail 4 in a similar way as the loadsensor 80, and the mounting instruction for the right front load sensor70 is the same as the case of the right rear load sensor 80. That is,the slide plate 79 disposed in a same way as the slide plate 89 isgrasped by the pawls to the lower surface of the frange 71, and thelevel screw 77 which is inserted into the damper 101 and the slidemember 102 comes through the elongated hole 75 from above to be engagedwith the movable upper rail 4 so as to erect it on the upper surface ofthe movable upper rail 4, the level screw 78 which is inserted into thedamper 103 and the slide member 104 is engaged with the movable upperrail 4 so as to erect it on the upper surface of the movable upper rail4, and the level screw 78 is inserted into the notch 76 by the rotationof the right front load sensor 70. Because the level screw 77 can slidein the longitudinal direction of the elongated hole 75 and the levelscrew 78 can slide in the longitudinal direction of the notch 76, theload sensor 70 can slide in a left-and-right direction with respect tothe right movable upper rail 4 in the range between the point where thelevel screw 77 abuts the right end of the elongated hole 75 and thepoint where the level screw 77 abuts the left end of the elongated hole75. Here, the tip of the connector 74 is directed backward for the rightfront load sensor 70, while the tip of the connector 84 is directedforward for the right rear load sensor 80.

As shown in FIGS. 2 and 3, the sub frame 110 in a shape of a rectangleframe which becomes a part of the seat cushion frame is mounted andfixed on the four load sensors 50, 60, 70, and 80. The sub frame 110comprises a left patch member 111 which extends in a front-and-reardirection, a right patch member 112 which extends in a front-and-reardirection to become parallel with the patch member 111, a cross pipe 113which is crosses between the rear ends of the patch members 111 and 112,and a front member 114 which crossed between the front ends of the patchmembers 111 and 112.

The patch member 111 is a metal material having a web 115 and left andright franges 116 and 117, and is U-shaped in section. The length of theweb 115 in a front-and-rear direction is longer than the length of thefranges 116 and 117 in a front-and-rear direction, the front end of theweb 115 projects more in front than the front ends of the franges 116and 117, and the webs 115 and 116 are not provided on the left and rightof the front end of the web 115. The right patch member 112 is also ametal material having the web 118 and the left and right franges 119 and120, and is U-shaped in section, and the webs 119 and 120 are notprovided at the left and right of the front end of the web 118. Themounting hole 121 is formed at the front end of the web 115 of the leftpatch member 111 and the mounting hole 122 is formed at the rear end ofthe web 115 to penetrate in an up-and-down direction. The mounting hole123 is formed at the front end of the web 118 of the right patch member112 to penetrate in an up-and-down direction, and the mounting hole 124is formed at the rear end of the web 118 to penetrate in an up-and-downdirection.

The front member 114 is a metal material having the web and front andback franges, and is U-shaped in section. The left end of the frontmember 114 is welded to the upper surface of the projected front end ofthe web 115, and the right end of the front member 114 is welded to theupper surface of the projected front end of the web 116. A harness whichis connected to the connectors 54, 64, 74, and 84 of the load sensors50, 60, 70, and 80 is applied to the front member 114 by clips.

The mounting hole is formed to penetrate in a left-and-right directionat the rear end of the frange 116 of the left patch member 111, thecross pipe 113 is inserted into this mounting hole, and further, thecross pipe 113 and the frange 116 are fixed by welding. The mountinghole which penetrates in a left-and-right direction is also formed atthe rear end of the frange 119 of the right patch member 112, the crosspipe 113 is inserted in this mounting hole, and the cross pipe 113 andthe frange 119 are fixed by welding.

The sub frame 110 which is assembled as described above is disposed tothe load sensor 50, 60, 70, and 80 as described below. The load inputrod 53 of the left front load sensor 50 is inserted into the mountinghole 121 of the left patch member 111 from bottom up and the front endof the left patch member 111 is mounted on the sensing unit 52. Then,the washer 131 is provided around the load input rod 53 as a ring, thenut 132 engages with the load input rod 53, the washer 131 and the web115 are held between the nut 132 and the upper surface of the sensingunit 52, and the load input rod 53 is fixed to the front end of the leftpatch member 111 by the tightening of the nut 132. Similarly, the loadinput rod 73 is inserted into the mounting hole 123 and the washer 135from bottom and the rear end of the right patch member 112 is mounted onthe sensing unit 72. The load input rod 73 is fixed to the front end ofthe right patch member 112 by the tightening of the nut 136 which isengaged with the load input rod 73.

Similarly for the rear load sensors 60 and 80, by the tightening of thenuts 134 and 138 which are engaged with the load input rods 63 and 83that are inserted into the mounting holes 122 and 124 and the washer 133and 137 from bottom, the load input rods 63 and 83 are fixed to the rearend of the patch members 111 and 112.

Here, because the right load sensors 70 and 80 are disposed to beslidable in a left-and-right direction with respect to the right movableupper rail 4, each of the mounting holes 121 to 124 can be fitted to theload input rods 53, 63, 73, and 83, respectively, with minor adjustmentsof the load sensors 70 and 80 in a left-and-right direction. Therefore,when the sub frame 110 is disposed, the initial deformation of the subframe 110 and the like can be prevented, and the initial load to theload sensor 50, 60, 70, and 80 can be eliminated.

The sub frame 110 is assembled by welding in advance before disposing tothe load sensor 50, 60, 70, and 80. However, when the sub frame 110 isassembled, the patch member 111, the patch member 112, the cross pipe113, and the front member 114 are fixed by the jig so that each of themounting holes 121 to 124 can fit to the load input rods 53, 63, 73, and83, respectively. Therefore, the load input rods 53, 63, 73, and 83 canbe matched and inserted into each of the mounting holes 121 to 124,respectively, without deforming the assembled sub frame 110.

As shown in FIG. 3, in a state where the sub frame 110 is disposed onthe load sensors 50, 60, 70, and 80, when seen from above as a planview, the front member 114 is positioned more in front than thesubmarine pipe 11.

As shown in FIGS. 1 and 3, the side frame 141 is welded to the frange116 outside of the patch member 111, and the side frame 142 is welded tothe frange 119 outside of the patch member 112. The side frames 141 and142 are parts of the seat cushion frame, and particularly, constitutethe side portion of the seat cushion frame. Further, the sub frame 110reinforces the side frames 142 and 142 as a part of the frame of theseat cushion. Before disposing the sub frame 110 on the load sensors 50,60, 70, and 80, the side frames 141 and 142 are disposed to the subframe 110 by welding. In FIG. 2, to make the drawing easier to be seen,the side frames 141 and 142 are omitted from the drawing.

A gouged section 151 dinted to the left is formed at the front of theleft side frame 141 so as to avoid the load rod 53 of the load sensor 50and the mounting hole 121, and a gouged section 152 dinted to the leftis formed at the rear of the side frame 141 so as to avoid the load rod63 of the load sensor 60 and the mounting hole 122. Because these gougedsections are formed, maintenance of the load sensors 50 and 60 can bedone from above and the nuts 53 and 63 can be rotated without beingdisturbed by the side frame 141. As described above, maintenance and thelike of the load sensor 50 and 60 can be done without dismounting theside frame 141 from the sub frame 110. Therefore, the efficiency of themaintenance of the load sensors 50 and 60 is improved.

Further, a gouged section 153 dinted to the right is formed at the frontof the right side frame 142 so as to avoid the load rod 73 of the loadsensor 70 and the mounting hole 123, and a gouged section 154 dinted tothe right is formed at the rear of the side frame 141 so as to avoid theload rod 83 of the load sensor 80 and the mounting hole 124. Becausethese gouged sections 153 and 154 are formed, maintenance of the loadsensors 70 and 80 can be done from above and the nuts 73 and 73 can berotated without being disturbed by the side frame 142.

As shown in FIG. 1, the front parts of the side frames 141 and 142 arecovered by the pan frame 143 from above, and the gouged sections 151 and153 are blocked by the pan frame 143 at the upper side of the loadsensors 50 and 70. The pan frame 143 is tightened with respect to theside frames 141 and 142 by the bolt 144 as a male screw. Moreover, asshown in FIG. 9, the pan frame 143 can be dismounted by loosening thebolt 144. The pan frame 143 may be tightened to the side frame 141 and142 by other male screw instead of the bolt 144. In FIG. 2, to make thedrawing easier to be seen, the pan frame 143 is omitted from thedrawing.

Because the pan frame 143 is detachably disposed on the side frames 141and 142, the maintenance of the load sensors 50 and 70 can be done justby dismounting the pan frame 143 and without decomposing/disassemblingthe side frames 141 and 142 and the sub frame 110. Therefore, theefficiency of the maintenance of the load sensor 50 and 70 is improved.

The pan frame 143 is disposed on the side frames 141 and 142 by lockingthe locking unit formed on the pan frame 143 with the locking unitformed on the side frames 141 and 142, and the pan frame 143 can bedetached from the side frames 141 and 142 by elastically deforming bothof the locking units.

The seat spring 145 is crossed between the cross pipe 113 and the panframe 143. A cushion is mounted on the pan frame 143 and the seat spring145, and the cushion, the pan frame 143, and the side frames 141 and 142are covered with a cover entirely.

The backrest frame is connected to the rear end of the side frames 141and 142. The backrest frame is disposed to be rotatable in afront-and-rear direction centering the connecting unit which connectsthe backrest frame to the side frames 141 and 142. The backrest frame isomitted from the drawing to make the drawing easier to be seen.

In the passenger's weight measurement device 1 configured as describedabove, when a passenger sits on the seat cushion, the weight (bodyweight) of the passenger is applied to the load sensors 50, 60, 70, and80 through the sub frame 110, and the weight of the passenger isdetected by the load sensors 50, 60, 70, and 80 as an electrical signal.

Here, each one of the load sensors 50, 60, 70, and 80 is disposedbetween the movable upper rail 4 and the side frames 141 and 142, so asto attach one sensor in the front and one sensor in the rear. The loadsensors 50, 60, 70, and 80 are configured to move in a front-and-reardirection as a unit with the vehicle seat. Therefore, despite of theposition of the vehicle seat in a front-and-rear direction, the load(weight of a passenger) transmitted to the load sensors 50, 60, 70, and80 from the vehicle seat can be consistently kept constant. Thus, theaccuracy of the passenger's weight measurement can be improved.

Further, the right load sensors 70 and 80 can slide in a left-and-rightdirection with respect to the movable upper rail 4. Therefore, even whenthe load is applied in a left-and-right direction with respect to thesub frame 110 and the like, the load escapes due to the sliding of theload sensors 70 and 80 and the load in a left-and-right direction is notapplied to the load sensors 50, 60, 70, and 80. Thus, the accuracy ofthe passenger's weight measurement can be improved.

While the right load sensors 70 and 80 can slide with respect to theright movable upper rail 4, the left load sensors 50 and 60 are fixed tothe left movable upper rail 4. Therefore, the entire vehicle seat doesnot sway in a left-and-right direction and the minimum rigidity as avehicle seat is assured.

Moreover, because the submarine pipe 11 is located more in rear than thefront member 114, when a frontward inertia force is applied to thepassenger due to a front collision or the like of the vehicle, thebuttocks of the passenger seated on the vehicle seat are held by thesubmarine pipe 11. Therefore, so-called submarine phenomenon where thepassenger gets under the waist belt can be prevented.

Further, because the submarine pipe 11 is provided separately from thefront member 114, the buttocks of the passenger do not hit against thefront member 114 at the time of front collision or the like of thevehicle. Therefore, the forward inertia force at the time of frontcollision or the like of the vehicle is not transmitted to the loadsensors 50, 60, 70, and 80 through the sub frame 110. Thus, the accuracyof the passenger's weight measurement can be improved even at the timeof front collision or the like of the vehicle.

Moreover, because the buttocks of the passenger are held by thesubmarine pipe 11 at the time of front collision or the like of thevehicle, there is a case where the submarine pipe bends forward inconvex. Here, because the right end of the submarine pipe 11 can move ina left-and-right direction with respect to the bracket 9 and is notfixed to the bracket 9, the load is not transmitted to the load sensors50, 60, 70, and 80 even when the forward load is applied to thesubmarine pipe 11. Thus, the accuracy of the passenger's weightmeasurement can be improved even at the time of front collision or thelike of the vehicle.

Further, because the sub frame 110 is assembled beforehand, each of theload input rods 53, 63, 73, and 83 can be matched and inserted into themounting holes 121 to 124, respectively, without deforming the assembledsub frame 110. Therefore, application of the initial load to the loadsensors 50, 60, 70, and 80 can be prevented when the load is not appliedto the sub frame 110. Thus, the accuracy of the passenger's weightmeasurement can be improved.

Further, only the webs 115 and 118 are provided at the front end of thepatch members 111 and 112, and the franges 116, 117, 119, and 120 arenot provided there. Therefore, because the patch members 111 and 112 aredeformed at the front end of the webs 115 and 118 thereof when a largeload is applied to the sub frames 110 at the time of front collision orthe like of the vehicle, the load is alleviated at the deformed portion.Therefore, a large load is not transmitted to the load sensors 50, 60,70, and 80, even when a large load is applied to the sub frame 110.Thus, the accuracy of the passenger's weight measurement can be improvedand the damage to the load sensors 50, 60, 70, and 80 can be suppressedeven at the time of front collision or the like of the vehicle.

In addition, because the top of the front load sensors 50 and 70 areopened when the pan frame 143 is dismounted, the maintenance of the loadsensors 50 and 70 can be done. Further, the present invention is notlimited to the embodiment described above. Various improvements anddesign changes can be made without departing from the gist of theinvention.

Modification Example 1

In the above described embodiment, the right load sensors 70 and 80 aredisposed to be slidable in a left-and-right direction with respect tothe movable upper rail 4. However, the right load sensor 70 and 80 mayfurther be disposed to be slidable in a left-and-right direction withrespect to the patch member 112. Moreover, the load sensors 70 and 80may be fixed to the movable upper rail 4 and may be disposed to beslidable in a left-and-right direction with respect to the patch member112. Here, in order to dispose the load sensors 70 and 80 to be slidablein a left-and-right direction with respect to the patch member 112, themounting holes 123 and 124 are formed as elongated holes lengthened in aleft-and-right direction, the load input rods 73 and 83 are insertedinto the ring-shaped slide member, and the slide member is held betweenthe washers 135 and 137 and the web 118. In addition, in order to fixthe load sensors 70 and 80 to the movable upper rail 4, the load sensors70 and 80 are fixed to the movable upper rail 4 in a similar way as theleft load sensors 50 and 60.

Modification Example 2

In the above described embodiment, the passenger's weight measurementdevice 1 is mounted on the right vehicle seat. However, the passenger'sweight measurement device 1 may be mounted on the left vehicle seat. Thepassenger's weight measurement device for the left vehicle seat isstructured in symmetrical with respect to the passenger's weightmeasurement device 1 described in the above embodiment. That is, in thepassenger's weight measurement device for the left vehicle seat, theload sensors 70 and 80 which can slide in a left-and-right direction areon the left side and the fixed load sensors 50 and 60 are on the rightside.

Modification Example 3

In the above described embodiment, the franges 71 and 81 of the loadsensors 70 and 80 horizontally extend in a front-and-rear direction.However, the franges 71 and 81 of the load sensor 70 and 80 mayhorizontally extend in a left-and-right direction. The longitudinaldirection of the elongated holes 75 and 85 and the notches 76 and 86formed on the franges 71 and 81 is the left-and-right direction evenwhen the franges 71 and 81 extend in a left-and-right direction. Thewidth of the movable upper rail 4 in a left-and-right direction can benarrower when the franges 71 and 81 extend in a front-and-reardirection, as described in the above embodiment, as compared with thecase where the franges 71 and 81 extend in a left-and-right direction.

INDUSTRIAL APPLICABILITY

The passenger's weight measurement device can be applied widely to, forexample, car, train, and other vehicle seats.

1. A passenger's weight measurement device for a vehicle seat,comprising: a pair of right and left frame members for supporting thevehicle seat, the frame members extending in a front-and-rear direction;load sensors which are mounted on a front portion and a rear portion ofeach of the frame members; a first connecting member for connectingbetween rear load sensor attachment portions of the pair of right andleft frame members, the rear load sensor attachment portions attachingrear load sensors which are mounted to the rear portion of each framemember; and a second connecting member for connecting the pair of rightand left frame members in front of the first connecting member; whereina middle portion of the first connecting member is disposed higher withrespect to a plane of the frame members than the rear load sensorattachment portions, and wherein a middle portion of the secondconnecting member is disposed at a position lower with respect to aplane of the frame members than front load sensor attachment portionsfor attaching front load sensors mounted to the front portion of eachframe member.
 2. The passenger's weight measurement device as claimed inclaim 1, wherein both end attachment portions of the second connectingmember are arranged lower than both end attachment portions of the firstconnecting member.
 3. The passenger's weight measurement device asclaimed in claim 1, wherein in at least one frame member of the pair offrame members, a gouged portion is provided that faces one of the loadsensors.
 4. The passenger's weight measurement device as claimed inclaim 3, wherein the gouged portion is provided outside one of the loadsensors.
 5. A passenger's weight measurement device for a vehicle seat,comprising: a pair of right and left frame members for supporting thevehicle seat, the frame members extending in a front-and-rear direction;load sensors which are mounted on a front portion and a rear portion ofeach frame member; a first connecting member for connecting between rearload sensor attachment portions of the pair of right and left framemembers, the rear load sensor attachment portions attaching rear loadsensors which are mounted on the rear portion of each frame member; anda second connecting member for connecting the pair of right and leftframe members in front of the first connecting member; wherein a middleportion of the first connecting member is disposed higher with respectto a plane of the frame members than the rear load sensor attachmentportions, wherein a middle portion of the second connecting member isdisposed lower with respect to a plane of the frame members than frontload sensor attachment portions for attaching front load sensors mountedon the front portion of each frame member, and wherein the middleportion of the second connecting member is disposed lower with respectto a plane of the frame members than lower surfaces of the pair of rightand left frame members.
 6. The passenger's weight measurement device asclaimed in claim 5, wherein both end attachment portions of the secondconnecting member are arranged lower than both end attachment portionsof the first connecting member.
 7. The passenger's weight measurementdevice as claimed in claim 5, wherein in at least one frame member ofthe pair of frame members, a gouged portion is provided that faces oneof the load sensors.
 8. The passenger's weight measurement device asclaimed in claim 7, wherein the gouged portion is provided outside oneof the load sensors.
 9. A passenger's weight measurement device for avehicle seat, comprising: a pair of right and left frame members forsupporting the vehicle seat, the frame members extending in afront-and-rear direction; load sensors which are mounted to a frontportion and a rear portion of each frame member; a first connectingmember for connecting between rear load sensor attachment portions ofthe pair of right and left frame members, the rear load sensorattachment portions attaching rear load sensors which are mounted on therear portion of each frame member; and a second connecting member forconnecting the pair of right and left frame members in front of thefirst connecting member; wherein a middle portion of the firstconnecting member is disposed higher with respect to a plane of theframe members than the rear load sensor attachment portions, wherein amiddle portion of the second connecting member is disposed lower withrespect to a plane of the frame members than front load sensorattachment portions for attaching front load sensors mounted to thefront portion of each frame member, and wherein both end portions of thesecond connecting member are wider than the middle portion of the secondconnecting member.
 10. The passenger's weight measurement device asclaimed in claim 9, wherein the middle portion of the second connectingmember is disposed lower than lower surfaces of the pair of right andleft frame members.
 11. The passenger's weight measurement device asclaimed in claim 9, wherein in at least one frame member of the pair offrame members, a gouged portion is provided that faces one of the loadsensors.
 12. The passenger s weight measurement device as claimed inclaim 11, wherein the gouged portion is provided outside one of the loadsensors.
 13. The passenger's weight measurement device as claimed inclaim 1, wherein a hole portion is formed at each of both end portionsof the second connecting member.
 14. The passenger's weight measurementdevice as claimed in claim 5, wherein a hole portion is formed at eachof both end portions of the second connecting member.
 15. Thepassenger's weight measurement device as claimed in claim 9, wherein ahole portion is formed at each of the both end portions of the secondconnecting member.
 16. The passenger's weight measurement device asclaimed in claim 1, wherein a cross section of a fixed frame forconnecting between an upper part of the front sensor attachment portionand an upper part of the rear load sensor attachment portion is formedin substantially a U-shape.
 17. The passenger's weight measurementdevice as claimed in claim 16, wherein an elongated hole that iselongated in the front-and-rear direction is formed in the fixed frame.18. The passenger's weight measurement device as claimed in claim 5,wherein a cross section of a fixed frame for connecting between an upperpart of the front sensor attachment portion and an upper part of therear load sensor attachment portion is formed in substantially aU-shape.
 19. The passenger's weight measurement device as claimed inclaim 18, wherein an elongated hole that is elongated in thefront-and-rear direction is formed in the fixed frame.
 20. Thepassenger's weight measurement device as claimed in claim 1, whereinconnectors of the front load sensors attached to the pair of the framemembers are disposed to face rearward along each frame member, andconnectors of the rear load sensors attached to the pair of the framemembers are disposed to face frontward along each frame member.